a hadrosaur, Sternberg (1932) suggested that Amblydactylus more closely resembled the footprints of Iguanodon. The majority of Amblydactylus tracks appear to have blunt hooves (fig. 1) and are relatively shorter and broader than Iguanodon tracks from England (Beckles 1856). The type specimen of Amblydactylus kortmeyeri is almost identical to hadro- saur footprints from the Upper Cretaceous of Alberta (Langston 1960).

A trackway worked on by the Royal Ontario Museum and numerous trackways found by the Provincial Museum of Alberta had handprints associated with the footprints of Amblydactylus. There is no evidence of the specialized "spike" on the hand, which is characteristic of Iguano- don. The handprints are roughly crescent shaped, and are remarkable for the lack of details indicating separation of fingers, no matter how well

HADROSAUR TRACKWAYS 65

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15 cm Fig. 1. Ambit/dactt/tus gethingi, PMA P78.11. Natural mould of a footprint (or

a natural cast of the foot) of a hadrosaurian dinosaur. the associated footprints are preserved. The hanciprints, however, are exactly the impression one would expect to find for a hadrosaur. It is known from "mummified" specimens (Osborn 1912; PMA P80.23.2) that the fingers of hadrosaurs were encased in a sheath of hide and were capable of only limited independent motion. It appears highly likely that the footprints of Amblydactylus represent hadrosaurian dinosaurs. This is significant because the earliest records of duckbilled dinosaurs from North America are Santonian in age (Kaye and Russell 1973}, whereas the beds in the Peace River Canyon are considerably older.

Sternberg collected a trackway of four footprints that he described as Irenesauripus occidentalis. The impressions are very shallow and the outlines are poorly defined. The relative width of the tracks, the width of the trackway and the shortness of stride are very different from Irenesauripus mclearni and I. acutus. Sternberg felt the different charact- 5 Acta Palaeontologica Polonlca Nr I — 2/83 66 PHILIP J. CURRIE ers of the trackway may be partly due to the slow movement of the animal when making the tracks. However, it is more likely that these four prints are synonymous with Amblydactylus. The divarication of digits II and IV is 73', much higher than that of I. mclearni and I. acutus, but within the range for Amblydactylus. As in Amblydactylus, the width of the foot is almost as great as the length. The average width to length ratio for the four tracks is.95. The stride length and width of the track- way are well within the range expected for Amblydactylus. Finally, it is worth pointing out that no other tracks were found that fit the descrip- tion of Irenesauripus occidentalis whereas Amblydactylus footprints are